Petroleum pitch-based carbon foam

Abstract

Petroleum or coal tar pitch-based cellular or porous products having a density of preferably between about 0.1 g/cm 3 and about 0.8 g/cm 3 are produced by the controlled heating of mesophase carbon materials derived from coal tar or petroleum pitch having a softening point in excess of about 300° C. and preferably between about 300 and about 400° C. in a “mold” and under a non-oxidizing atmosphere. The porous product thereby produced, preferably as a net shape or near net shape, can be machined, adhered and otherwise fabricated to produce a wide variety of low cost, low density products.

What is claimed is:  
     
       1. A porous pitch-based foam produced from a mesophase carbon derived from at least one of a petroleum pitch and a coal tar pitch exhibiting a softening point above about 300° C., and having a density ranging from about 0.1 to about 0.8 g/cm 3 . 
     
     
       2. The porous pitch-based foam of  claim 1  wherein said coal tar or petroleum pitch exhibits a softening point ranging from about 300° C. to about 400° C. 
     
     
       3. The porous pitch-based foam of  claim 1  having a compressive strength below about 6000 psi. 
     
     
       4. The porous pitch-based foam of  claim 1  that has been further carbonized. 
     
     
       5. The porous pitch-based foam of  claim 1  that has been further graphitized. 
     
     
       6. A method for producing a carbon foam from a mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C., comprising: 
       placing mesophase carbon particulate in a mold;  
       heating said mesophase carbon particulate in said mold under a non-oxidizing atmosphere to a temperature ranging from about 300° C. to about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 1 hour to form a green foam; and controllably cooling said green foam.  
     
     
       7. The method of  claim 6 , wherein said coal tar or petroleum pitch exhibits a softening point ranging from about 300° C. to about 400° C. 
     
     
       8. The method of  claim 6 , wherein said non-oxidizing atmosphere is applied at a pressure of from about 50 psi to about 500 psi. 
     
     
       9. The method of  claim 6 , wherein said temperature is achieved using a heat-up rate ranging from about 2° C. to about 10° C. per minute. 
     
     
       10. The method of  claim 6 , wherein said controlled cooling is accomplished at a rate of less than about 10° C./min to a temperature of about 100° C. 
     
     
       11. The method of  claim 6 , wherein said mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C. is produced by thermal treatment or solvent extraction of said petroleum or coal tar pitch. 
     
     
       12. A porous pitch-based foam produced from a mesophase carbon derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C., and having a density of ranging from about 0.1 to about 0.8 g/cm 3  produced by a method comprising: 
       placing mesophase carbon particulate in a mold;  
       heating said mesophase carbon particulate in said mold under a non-oxidizing atmosphere to a temperature of ranging from about 300° C. to about 700° C. to form a foam.  
     
     
       13. The porous pitch-based foam of  claim 12 , wherein said coal tar or petroleum pitch exhibits a softening point ranging from about 300° C. to about 400° C. 
     
     
       14. The porous pitch-based foam of  claim 12 , wherein said non-oxidizing atmosphere is applied at a pressure ranging from about 50 psi to about 500 psi. 
     
     
       15. The porous pitch-based foam of  claim 12 , wherein said temperature is achieved using a heat-up rate ranging from about 2° C. to about 10° C. per minute. 
     
     
       16. The porous pitch-based foam of  claim 12 , further comprising the step of controllably cooling the foam at a rate of less than about 10° C./min to a temperature of about 100° C. 
     
     
       17. The porous pitch-based foam of  claim 12 , wherein said mesophase carbon particulate derived from a petroleum or coal tar pitch exhibiting a softening point above about 300° C. is produced by thermal treatment or solvent extraction of said petroleum or coal tar pitch.